Film cutting device

ABSTRACT

A fixed cutter ( 15 ) is provided on a top surface ( 8   a ) of an adsorption type carrying belt ( 8 ) that carries a film. A cylindrical cutter holder ( 33 ) having a rotary cutter ( 16 ) is provided in the vicinity of the fixed cutter. The fixed cutter ( 15 ) has nearly a triangular cross section, and includes an inclined surface ( 15   a ) that guides the film on the top surface ( 8   a ) of the belt ( 8 ) to a blade edge ( 23 ) and a flank relief ( 15   b ) having nearly a V-shaped cross section. A vibration preventing hook that restricts a deformation caused by the toughness of the blade edge ( 23 ) is pressed against the flank relief A blade edge ( 37 ) of the rotary cutter ( 16 ) is disposed at an offset position. The film is cut by a relative operation of the blade edges ( 23, 37 ) while rotating the rotary cutter with respect to the fixed cutter ( 15 ). Both of the cutters ( 15, 16 ) are installed in a cutter unit, and are fixed to a frame part of a packaging machine while performing positional adjustment. The fitting position of both cutters can be adjusted before the cutter unit is attached to a film cutting device.

TECHNICAL FIELD

The present invention relates to a film cutting device used to cut afilm carried by a conveying means, such as a conveyer, in order topackage goods, such as various articles of merchandise.

BACKGROUND ART

Generally, devices disclosed in Japanese Unexamined Utility ModelApplication Publication No. S53-121573, Japanese Examined PatentApplication Publication No. H2-23412, Japanese Unexamined PatentApplication Publication No. H4-40254, Japanese Unexamined PatentApplication Publication No. H10-15887, and Japanese Unexamined PatentApplication Publication No. 2002-211833 can be mentioned as examples ofthis type of film cutting device. These film cutting devices are used tocut a continuous belt-like film into predetermined lengths while drawingthe film from a roll, so as to package various articles of merchandisewith the film.

Japanese Unexamined Utility Model Application Publication No. S53-121573relates to a thin-paper rotary cutting device comprised of convex bladesand flat receiving blades, in which the convex blade is formed to have aconcavely curved shape, and cuts a thin sheet of paper in a state ofbeing slightly inclined with respect to the flat receiving blade,thereby making its blade touching uniform.

Japanese Examined Patent Application Publication No. H2-23412 relates toa device for cutting a film with a cutting knife provided on anadsorption drum and with a rotary opposed knife while winding the filmdrawn out on the adsorption drum, in which neither jamming nor apositional deviation occurs when the film is cut, because the film iscut in the state of being adsorbed onto the adsorption drum.

As in Japanese Examined Patent Application Publication No. H2-23412,Japanese Unexamined Patent Application Publication No. H4-40254 relatesto a device in which a film is cut while winding the film on a roller,so that neither jamming nor a positional deviation occurs when the filmis cut.

Japanese Unexamined Patent Application Publication No. H10-15887 relatesto a cutting device in which a lower blade of a rotary cutter is causedto depart from a position to butt against an upper blade and iselastically deformed when a sheet of paper or the like is cut, so that acutting operation is performed with the lower and upper blades by meansof an elastic return force generated by the toughness of the lowerblade.

Japanese Unexamined Patent Application Publication No. 2002-211833relates to a device for cutting a narrow tear tape being fed topackaging sheets, in which a slope cutter that serves as a receivingblade is provided at the middle of a conveying adsorption belt thatconveys a tape, and the time during which a tape is not adsorbed isshortened by cutting the tape in the vicinity of a film-conveying planethat meets the tape, thereby preventing the tape from being crumpled sothat the tape can be conveyed straight.

However, with regard to the film cutting device mentioned above, that ofJapanese Unexamined Utility Model Application Publication No. S53-121573has a disadvantage in that the convex blade cannot be easily formed tohave a concavely curved shape, and it is difficult to adjust the bladebutting between the convex blade and the flat receiving blade. That ofJapanese Examined Patent Application Publication No. H2-23412 and thatof Japanese Unexamined Patent Application Publication No. H4-40254 havea disadvantage in that the adsorbing device must be provided not only onthe conveying belt but also on the adsorption roller, and the film iswound on the adsorption roller and is drawn out toward the deflectionroller, thus increasing the number of rollers and producing a complex,high-cost device. That of Japanese Unexamined Patent ApplicationPublication No. H10-15887 has a disadvantage in that a blade-touchingadjustment is difficult since the blade is elastically deformed by thetoughness of the blade when a film or the like is cut.

That of Japanese Unexamined Patent Application Publication No.2002-211833 is a device for cutting a narrow tear tape, and cannot cut apackaging film much wider than the tear tape with high precision.Especially when two blades are provided in a crossed manner, and acutting edge of one of the two blades is butted against a cutting edgeof the other blade so as to cut a film in point contact as if with apair of scissors, a blade width becomes greater, and, unlike the teartape, the width of the film to be cut becomes greater. Therefore, thecutting edge largely departs because of its blade toughness, and,disadvantageously, a precise cutting operation cannot be performed.

The present invention has been made in consideration of thesecircumstances, and aims to provide a film cutting device capable ofeasily performing a blade touching adjustment and capable of cutting anykind of film with high accuracy even if the film is wide.

DISCLOSURE OF INVENTION

The film cutting device according to the present invention ischaracterized in that the film cutting device includes a conveying meansfor conveying a film, a first cutter that is provided on the conveyingmeans and that has a blade edge at an end of a guide surface inclined ina direction receding from the conveying means, and a second cutter thatcuts a film placed on the guide surface in cooperation with the bladeedge of the first cutter, and in that the first cutter and the secondcutter are relativity moved, and the blade edge of the first cutter anda blade edge of the second cutter are gradually engaged with each otherin an extending direction thereof, thus cutting the film.

A film carried by the conveying means can be cut in its width directionby being guided by the guide surface so as to be separated from theconveying means and by engaging the blade edge provided at the end ofthe guide surface of the first cutter and the blade edge of the secondcutter with each other.

The conveying means is an adsorption type carrying belt that adsorbs thefilm. Since the film being carried is adsorbed, film can be carriedregardless of the difference in the kind of film, such as a differencein rigidity of the film or a difference in tension of the film.Moreover, the film can be sent to a film cutting position while smoothlyseparating the film from the adsorption type carrying belt along theguide surface.

The blade edge of the first cutter is elastically deformable, and thefirst cutter may be provided with a displacement restricting member thatrestricts an elastic deformation of the blade edge when the film is cut.

If the blade edge of the first cutter is elastically deformable bytoughness or ductility, it is possible to absorb minute pressure-contactchaotic movement of the blade edge resulting from an error in dimensionor an error in assemblage between both the first and second cutters whenthe blade edge of the first cutter cuts a film while being pressed tocome into contact with the second cutter. In a case in which a wide filmis cut, the distance of blade touching of the cutter becomes long whenthe cutter is pressed to come into contact with the other one, so thatthe blade edge deviates, and the sharpness of the cutter is reduced.However, according to the present invention, since the displacementrestricting member restricts the deviation of the blade edge of thefirst cutter, the sharpness of the cutter can be maintained, and thefilm can be cut with high accuracy.

Instead of the first cutter, or, alternatively, together with the firstcutter, the blade edge of the second cutter may be formed to beelastically deformable by toughness, and the second cutter may beprovided with a displacement restricting member.

The first cutter may be shaped like a wide band, and the displacementrestricting member may be provided in a central area in an extendingdirection of the blade edge of the first cutter.

If the film, which is a sheet of material, is wide, the first and secondcutters must be formed to be wide, and, when the first and secondcutters cut the film while being pressed against each other, the firstand second cutters are greatly deformed because of their toughness orductility at their central areas. In this case, the amount of deviationof the entire blade edge resulting from the toughness can be restrictedby providing the displacement restricting member in the central area inthe extending direction of the blade edge of the first cutter.

The displacement restricting member may be in contact with a flankrelief of the first cutter that is crossed with the guide surface at theblade edge thereof.

The deviation of the blade edge due to toughness occurring when thecutters are pressed against each other can be controlled by bringing thedisplacement restricting member into contact with the flank relief ofthe first cutter.

The second cutter is a rotary cutter rotatable around a rotationalshaft, and the blade edge of the second cutter may be installed so thata cutting force acts toward the first cutter when a film is cut.

If a cutting force acts toward the first cutter at all steps performedwhen a film is cut, it is possible to absorb minute pressure-contactchaotic movement of the blade edge resulting from an error in dimensionor an error in assemblage between both the first and second cutters.Therefore, it is recommended to dispose the second cutter at an offsetposition.

The second cutter may guide the following film in a direction of theconveying means by use of a backface of the second cutter on a rear sidein a moving direction subsequent to the blade edge thereof.

After cutting the film through a relative operation of the blade edgesof the first and second cutters, a film part following the film that hasbeen cut is pressed down by the backface of the second cutter. Thereby,the film part can be guided onto the conveying means positioned in frontof the first cutter.

The first and second cutters are held together as a cutter unit, and canbe adjusted by being detached from the conveying means.

Since an engagement position of the first and second cutters can beindependently adjusted in a state in which the cutters are separatedfrom the conveying means, it is possible to perform excellentmaintenance of the positioning of the blade edges or replacement ofconstituent elements.

The cutter unit may be disposed so as to be adjustably positioned in thedirection in which the film is carried by the conveying means.

Since the position at which the film being carried by the conveyingmeans is cut can be adjusted in forward and backward directions, thewhole of the device can be made compact so as to be superior in sizereduction and in economy, and a cutting adjustment can be easilyperformed according to a difference in kind or usage of the film.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view that roughly explains a process forgathering goods into accumulation units and packaging each unit in anaccumulating and packing machine including a film cutting deviceaccording to the embodiment of the present invention.

FIG. 2 is a front view of the film cutting device.

FIG. 3 is a right side view of the film cutting device of FIG. 2.

FIG. 4 is a plan view of the film cutting device of FIG. 2 in which arotary cutter is omitted.

FIG. 5 is an enlarged view of a fixed cutter and a rotary cutter of acutter unit.

FIG. 6 is a schematic view showing a cutting step performed by the fixedcutter and the rotary cutter.

FIG. 7 is an explanatory drawing that explains the fixed cutter and avibration preventing hook.

FIG. 8 is a front view showing a cutter unit of a film cutting deviceaccording to a second embodiment of the present invention and anadsorption type carrying belt.

FIG. 9 is a front view of a main part showing a structure of a filmcutting device according to a modification.

BEST MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of the present invention will be hereinafterdescribed with reference to the drawings. It should be noted that thepresent invention is not limited to the embodiments described below,and, as an example, constituent elements of these embodiments may beappropriately combined.

Referring now to FIG. 1 to FIG. 7, a film cutting device according to anembodiment of the present invention will be described. FIG. 1 is aperspective view that roughly explains a process for gathering goodsinto accumulation units and packaging each unit in an accumulating andpacking machine including the film cutting device, FIG. 2 is a frontview of the film cutting device, FIG. 3 is a right side view of the filmcutting device of FIG. 2, FIG. 4 is a plan view of the film cuttingdevice of FIG. 2 in which a rotary cutter is omitted, FIG. 5 is anenlarged view of a fixed cutter and a rotary cutter of a cutter unit,FIG. 6 is a schematic view showing a cutting step performed by the fixedcutter and the rotary cutter, and FIG. 7 is an explanatory drawing thatexplains the fixed cutter and a vibration preventing hook.

The accumulating and packing machine 1 shown in FIG. 1 is to packagegoods with a packaging material, such as a plastic film f. For example,the goods are a rectangular solid-shaped box, such as a tissue box(hereinafter, referred to simply as “box”) b, and an appropriate numberof boxes (e.g., five boxes) arranged in close contact with each otherare packaged as a unit (i.e., an accumulation unit B).

A packaging process is performed by the accumulating and packing machine1 as follows. First, boxes b sequentially produced are arranged in thesame direction while being brought into close contact with each other,and are carried by an accumulating and conveying machine 2. Thereafter,in a conveying step, adjoining boxes b are spaced at predeterminedintervals, and five boxes are brought into contact with each other so asto form an accumulation unit B. Thereafter, each accumulation unit Bconsisting of five boxes is sent upward.

On the other hand, in a packaging machine 3, a plastic film fo, which ismade of, for example, polyethylene and which is wound on a roll 4, isdrawn from the roll 4, and is cut into predetermined lengths by a filmcutting device 5. A rising accumulation unit B is then placed against afilm f cut thereby from below, and is packaged with the film f in a bodyfolding manner. Thereafter, the accumulation unit B is sealed bysubjecting the ends of the film f to, for example, thermo-compressionbonding.

A description will be hereinafter given of the film cutting device 5that cuts a continuous band-shaped film fo having a width of, forexample, about 780 mm into predetermined lengths in the accumulating andpacking machine 1 having the step of accumulating the boxes b and thestep of packaging the boxes b with the film f.

The packaging machine 3 of FIG. 1 is disposed on an extension of a flatbelt conveyer of the accumulating and conveying machine 2 carrying theboxes b in such a way as to substantially face the accumulating andconveying machine 2. The film fo drawn out from the roll 4 is fed to thefilm cutting device 5 from a guide roll via a dancer roller 7.

In the film cutting device 5 shown in FIGS. 2 to 4, an adsorption typecarrying belt (conveying means) 8 used to place and carry the film fothereon is extended to above the flat belt conveyer of the accumulatingand conveying machine 2 of the boxes b so as to overlap with the flatbelt conveyer. The adsorption type carrying belt 8 is formed being woundendlessly between a pair of driving rollers 9 a and 9 b provided on bothsides in the conveying direction. The driving roller 9 a, which is oneof the two rollers, receives a driving force of a motor M1, therebyorbitally moving the adsorption type carrying belt 8. For example, theadsorption type carrying belt 8 is made up of two endless belts 8A and8A disposed on both ends in the width direction of the film fo and one(or more) endless belt 8B (see FIG. 4) disposed between the belts 8A and8A.

A long adsorption box 10 is provided at the lower side of a top surface8 a of the adsorption type carrying belt 8 that is extended in theconveying direction of the film fo, and the adsorption box 10 is broughtinto contact with the top surface 8 a of the belt by means of a pressingroller 11. Since through-holes 8 b are bored in the adsorption typecarrying belt 8 at predetermined intervals upward and downward, the filmfo is carried while being adsorbed by the top surface 8 a of the belt(see FIG. 5).

A cutter unit 13 that cuts the film fo into predetermined lengths isdisposed on a middle part in the conveying direction of the adsorptiontype carrying belt 8. The cutter unit 13 has a frame 14 extending fromabove the adsorption type carrying belt 8 downward and extending in thewidth direction. The frame 14 holds a fixed cutter 15 and a rotarycutter 16 both of which cut the film fo through their relativeoperation.

The frame 14 has a pair of horizontal frame parts 18, which are disposedperpendicularly to the conveying direction on both the upper and lowersides of the adsorption type carrying belt 8, and a pair of side frameparts 19, which are disposed vertically on both the outsides in thewidth direction of the adsorption type carrying belt 8 and which areconnected to both ends of the horizontal frame parts 18. As shown inFIGS. 3 and 4, one (or both) of the side frame parts 19 is fixed to amain frame 3 a of the packaging machine 3 that extends in the extendingdirection of the adsorption type carrying belt 8 with one or more fixingmembers 20, such as bolts, through an intermediary member 19 a. Eachbolt 20 is fixed to the side frame 19 through each long hole 21 bored inthe main frame 3 a. Within the range of each long hole 21, the fittingposition of the cutter unit 13 can be adjusted in the forward andbackward directions in which the adsorption type carrying belt 8extends.

The fixed cutter 15 is slightly spaced apart from and floats above thetop surface 8 a of the adsorption type carrying belt 8 especially asshown in FIG. 5. An inclined surface (guide surface) 15 a, which is atop surface of the fixed cutter 15, gradually recedes from the topsurface 8 a of the belt 8 from the upstream side to the downstream sideof the top surface 8 a, and has a substantially triangular longitudinalsection. As shown in FIG. 5, the inclined surface 15 a is formed as atwo-step inclined surface, and the oblique angle of the inclined surfaceon the downstream side is smaller than that on the upstream side. Thefixed cutter 15 extends in the width direction of the adsorption typecarrying belt 8, and is equal at least in width to the film fo.Therefore, the film fo is carried while being adsorbed by the topsurface 8 a of the belt 8, is then scooped by the fixed cutter 15 alongthe inclined surface 15 a, and is carried in the direction receding fromthe top surface 8 a of the belt 8.

In the fixed cutter 15, a crossed ridge line between an end on thedownstream side of the inclined surface 15 a and a flank relief (i.e., arecess) 15 b facing the downstream direction of the top surface 8 a ofthe belt 8 serves as a straight blade edge 23 extending in the widthdirection of the top surface 8 a of the belt 8. The blade edge 23 is setat a low height h (e.g., about 3 to 5 mm) from the top surface 8 a ofthe belt 8. For example, the flank relief 15 b has a runaway grooveshaped substantially like the letter V or like a concave curve whenviewed as a longitudinal section. Therefore, the wedge angle of theblade edge 23 formed by the inclined surface 15 a and the flank relief15 b is set to be acute (alternatively, it is permissible for it to beobtuse). As a result, when the film fo is cut, the blade edge 23receives a load of the rotary cutter 16 through a mutual operation withthe rotary cutter 16, and can exhibit ductility (i.e., toughness) bywhich the blade edge 23 is elastically deformed.

Since the flank relief 15 b is formed to have a runaway groove or sincethe wedge angle is set to be acute, minute pressure-contact chaoticmovement of the blade edge 23 caused by an error in dimension or anerror in assemblage can be absorbed by its toughness when the fixedcutter 15 cuts a film in cooperation with the rotary cutter 16.

As shown in FIGS. 2 and 3, the fixed cutter 15 is fixed between the sideframes 19 and 19 of the cutter unit 13 through a supporting arm part 25.The supporting arm part 25 is made up of a first base 26, a second base27, and arm parts 28. In detail, the first base 26 shaped substantiallylike a plate is fixed between the pair of side frames 19 and 19 in astate of being inclined obliquely upward, and the second base 27 isfixed with, for example, a screw in a state of being directed upward andbeing substantially perpendicular to the first base 26. The plurality ofarms 28 (four arms 28 in FIG. 3) are attached to the second base 27 atpredetermined intervals in the width direction of the top surface 8 a ofthe belt 8 so as to be movable forward and backward in its longitudinaldirection. The bottom 15 c of the fixed cutter 15 is attached to thefront end surface of each arm 28 directed upward.

In the supporting arm part 25, a positioning pin 24 that determines thecrossed position of the second base 27 with respect to the first base 26is provided at a connected portion between the first base 26 and thesecond base 27, and the first and second bases 26 and 27 are fixedtogether with a bolt 29 or the like. A blade-touching adjustment bolt(blade touching adjustment member) 30 that passes through the first base26 and that presses the rear end surface of each arm 28 is screwed tothe first base 26. The blade touching of the fixed cutter 15 througheach arm 28 can be adjusted by rotating and moving back and forth theblade-touching adjustment bolt 30. Each arm 28 has a long hole 28 b, andis fixed to the second base 27 with a fixing bolt 31 or the like so thatthe arm 28 can move to or from the second base 27 through the long hole28 b.

Therefore, the blade-touching adjustment bolt 30 is moved back and forthin a state in which each fixing bolt 31 is loosened, and the blade edge23 of the fixed cutter 15 is moved back and forth through each arm 28,thus adjusting the blade touching.

As shown in FIG. 5, the rotary cutter 16 is disposed on an outerperipheral surface 33 a of a rotatable cylindrical cutter holder 33along a rotational shaft 34. The cutter holder 33 is disposed above thetop surface 8 a of the belt 8 in such a way so as to have a slight gaptherebetween and so as to face the fixed cutter 15. A concave part 35whose cross section is shaped like the letter L is formed in the outerperipheral surface 33 a of the cutter holder 33 along the rotationalshaft 34. The rotary cutter 16 is fixed to the concave part 35 with, forexample, a bolt 36 substantially perpendicular to the radius line of thecutter holder 33 (i.e., substantially in the direction of a tangentialline of the outer peripheral surface 33 a).

The rotary cutter 16 is shaped substantially like a plate extending inthe width direction of the adsorption type carrying belt 8. A convexcurved surface. (backface) 16 a, which is an upper surface of the rotarycutter 16, slightly juts out from the outer peripheral surface 33 a, andis convexly curved along the outer peripheral surface 33 a.

A head 36 a of the bolt 36 is placed onto a concave groove 16 b hollowedtoward the rotational shaft 34 of the cutter holder 33 from the convexcurved surface 16 a, thereby sinking inward from the convex curvedsurface 16 a.

In the rotary cutter 16, the ridge part ahead in the rotationaldirection of the convex curved surface 16 a serves as a blade edge 37.For example, the blade edge 37 is straight extending in the widthdirection of the adsorption type carrying belt 8, and is longer than thewidth of the film fo, and is installed in a cutter-crossed manner inwhich the cutters are relatively inclined so that the blade edge 37 canbe crossed with the blade edge 23 of the fixed cutter 15 at apredetermined angle. The blade edge 37 of the rotary cutter 16 isdisposed at an offset position deviated by a distance D behind in therotational direction from the rotational center O of the cutter holder33 with respect to a virtual reference line L drawn substantially inparallel with the forward and backward direction of the blade edge 23 ofthe fixed cutter 15.

Therefore, when the cutter holder 33 is rotated around the rotationalshaft 34 so as to rotate the rotary cutter 16, the blade edge 37 of therotary cutter is pressed against the blade edge 23 of the fixed cutter15, for example, from one of the ends of the blade edge 37, and isbrought into point contact therewith at the beginning of cutting asshown in FIG. 6. In proportion to an advance in the rotation of theblade edge 37, a contact point between the blade edges 37 and 23 movesgradually, and the other end of the blade edge 37 is reached to come tothe end of cutting. Therefore, the fixed cutter 15 and the rotary cutter16 perform a scissors-like cutting operation.

Since the blade edge 37 of the rotary cutter 16 is offset by thedistance D, a precise cutting operation can be performed by allowing aload F generated by the rotation of the blade edge 37 to act in adirection being pressed against the blade edge 23 which is a receivingblade from the beginning of cutting to the end of cutting. A rotationlocus of the blade edge 37 is set to be greater than the convex curvedsurface 16 a (see FIG. 5).

As shown in FIG. 3, the rotational shaft 34 extends to both sides of thecutter holder 33, and is rotatably supported by thrust bearings 39 and39 provided on the side frames 19 and 19, respectively, and juts outtherefrom. A blade-touching adjustment handle 40 is provided on one endof the rotational shaft 34. The blade edge 37 of the rotary cutter 33can be adjusted so as to move radially back and forth from the inside ofthe cutter handle 33 by reversely and positively rotating the handle 40.A crossed angle of the blade edge 37 with the blade edge 23 can also beadjusted by reversely and positively rotating the handle 40.

A coupling part 41 a is provided on the other end of the rotationalshaft 34, and forms a coupling that transmits a driving force to thecutter holder 33 by coming into plane contact with a coupling part 41 bconnected to an output shaft of a cutter drive motor M2.

As shown in FIG. 3, the fixed cutter 15 is greater in length in thewidth direction of the adsorption type carrying belt 8 than the rotarycutter 16, and two arms 28 and 28 are provided on both ends in thelengthwise direction of the fixed cutter 15. Two arms 28 and 28 with aninterval therebetween are also provided on the central part thereof.These are designated as central arm parts 28 a and 28 a, respectively.As shown in FIG. 7, a holding plate 43 is fixed to the side face of eachcentral arm part 28 a closer to the flank relief 15 b of the fixedcutter 15 with, for example, a screw. For example, a planarvibration-preventing hook (displacement restricting member) 44 is fixedto the front end surface of the holding plate 43 while the front endsurface of the hook 44 is being pressed against the runaway groove ofthe flank relief 15 b of the fixed cutter 15. The vibration preventinghook 44 is omitted in FIG. 5.

The vibration preventing hook 44 can restrict runaway and twistingcaused by elastic deformation resulting from the toughness of the bladeedge 23 when the blade edge 37 of the rotary cutter 16 is pressedagainst the blade edge 23 of the fixed cutter 15 and performs ascissors-like cutting operation. Therefore, the film fo can be cut overits entire width while bringing the blade edge 37 and the blade edge 23into point contact with each other. The vibration preventing hook 44 maybe provided individually on each central arm part 28 a, or a planarmember formed integrally may be supported by the two central arm parts28 a and 28 a.

Since the fixed cutter 15 is shaped like a long, thin, and planar bandin order to cut the film fo and since both ends of the fixed cutter 15are supported by the arms 28 and 28, especially the central part thereofis elastically deformed because of its toughness, and deviates fromblade edge 37 of the rotary cutter 16, and is twisted, thus making itdifficult to perform a scissors-like cutting operation in its centralpart. For example, if the blade edge 23 deviates by several micronsbecause of toughness when the film fo is 20 μm in thickness, the filmcannot be cut. In this embodiment, since the film cutting device isstructured as above, a scissors-like cutting operation can be linearlyperformed while restricting deviation of the central part of the bladeedge 23 and being gradually crossed with the blade edge 37 of the rotarycutter 16 over the entire length thereof.

The vibration preventing hook 44 may be brought into contact with theflank relief 15 b over the whole length thereof.

The film cutting device 5 according to this embodiment is structured asdescribed above. The operation of the film cutting device 5 will now bedescribed.

First, only the cutter unit 13 is extracted before attaching the cutterunit 13 to the film cutting device 5, and the fitting position of thefixed cutter 15 is adjusted by the blade-touching adjustment bolt 30 ofthe supporting arm part 25. Likewise, the rotary cutter 16 is adjustedby the blade-touching adjustment handle 40. Thus, the positions of boththe cutters are adjusted so that the blade edge 37 of the rotary cutter16 rotating with respect to the blade edge 23 of the fixed cutter 15 canbe moved in a state of being in point contact with each other and canperform a scissors-like cutting operation.

Thereafter, the cutter unit 13 is passed between the adsorption typecarrying belts 8 and 8, and is fixed to the frame part 3 a of thepackaging machine 3. At this time, the cutter unit 13 is fixed theretoby adjusting the position of the cutter unit 13 in the conveyingdirection of the adsorption type belt 8 by means of the bolt 20 and thelong hole 21 of the frame part 3 a.

Thereafter, a continuous band-shaped film fo is drawn out from the roll4 of the packaging machine 3, and is carried to the top surface 8 a ofthe adsorption type carrying belt 8 of the film cutting device 5. Sincethe film fo is adsorbed by the adsorption box 10 through thethrough-hole 8 b on the top surface 8 a of the belt 8, the film fo iscarried without floating, regardless of the kind of the material of thefilm fo. When the film fo reaches the fixed cutter 15, the film fo isscooped by the gently inclined surface 15 a over the whole widththereof, and is gradually separated from the top surface 8 a of the belt8 over the whole width thereof. The film fo then smoothly proceeds tothe blade edge 23, which is the highest point to be reached by the filmfo, in a state of a low parallel wave.

Since the fixed cutter 15 does not have a through-hole for adsorption inthis embodiment, the effect of an adsorbing force by the adsorption box10 is diminished, and the film fo naturally proceeds without tensioneven if the film fo is materially thin and limp. Moreover, a leakagenegative pressure from the through-hole 8 b of the belt 8 is slightlyapplied between the top surface of the inclined surface 15 a and theback surface of the film fo, and a film-like air flow layer is partiallygenerated, and, accordingly, the film fo is adsorbed to the inclinedsurface 15 a by a slight force. Static electricity generated on the backsurface of the film fo is removed from the inclined surface 15 a intothe packaging machine 3 by means of a static electricity removing device(not shown).

The film fo that has gone beyond the blade edge 23 is pressed againstthe adsorption type carrying belt 8 in front of the fixed cutter 15 bymeans of the outer peripheral surface 33 a of the cutter holder 33.Thereafter, at a position where the cutter holder 33 has finished makingone rotation, the blade edge 37 of the rotary cutter 16 comes into pointcontact with one end of the blade edge 23 of the fixed cutter 15, andstarts cutting the film fo. Correspondingly to an advance in therotation of the rotary cutter 16, the contact point between the bladeedges 23 and 37 is moved in the direction in which the blade edgeextends, and the end of cutting is reached (see FIG. 6), thus completelycutting the film fo.

Since the rotary cutter 16 is offset by the distance D, a load Fgenerated by the rotation is imposed on the blade edge 23 from thebeginning of cutting to the end of cutting. Additionally, since theflank relief 15 b is shaped like the letter V or like a concave curvedsurface and since the wedge angle is set to be acute, an error indimension of the cutters 15 and 16 or an error in attachment thereof isabsorbed by the action of toughness, and the blade edge 23 of the fixedcutter 15 can reliably cut the film fo. Additionally, the vibrationpreventing hook 44 is pressed against the flank relief 15 b, and thequantity of runaway due to toughness is restricted in the central partof the blade edge 23 of the fixed cutter 15 that is liable to run awaymore greatly because of toughness than the other part of the blade edge23 since the blade edges 23 and 37 are great in width. Therefore, evenwhen a wide film fo is cut by the fixed cutter 15 shaped like a thinplanar band, the film fo can be cut over the whole width thereof withexcellent sharpness and with high accuracy without causing a cuttingbend or jamming.

The film fo following the cut plane of the film f is sent from the bladeedge 23 of the inclined surface 15 a of the fixed cutter 15, and isguided to the top surface 8 a of the belt 8 ahead while the front end ofthe film fo is being pressed by the convex curved surface 16 a followingthe blade edge 37 of the rotary cutter 16. Therefore, the front end ofthe film fo can be prevented from floating.

The film f that has been cut is carried above the accumulation unit B ofthe box conveying machine 2. The film f is then subjected to bodyfolding by the rising movement of the accumulated boxes (i.e.,accumulation unit) B, and packages the boxes B. In accordance with theconveyance of the film fo, the film fo is sequentially cut into apredetermined length per rotation of the rotary cutter 16, and theaccumulation units B are sequentially packaged according to the processmentioned above.

The length of the film f can be adjusted by the rotational speed of thedrive motors M1 and M2.

As described above, in the film cutting device 5 according to thisembodiment, the cutter unit 13 is extracted outside from the filmcutting device 5, and the blade touching of the blade edges 23 and 37can be adjusted. Therefore, the blade touching thereof can be easilyadjusted, and excellent maintenance is realized. Additionally, the filmcutting device 5 can be reduced in size by the cutter unit 13, andexcellent economy can be obtained. Additionally, since the cuttingposition can be easily changed on the adsorption type carrying belt 8,the film cutting device 5 is superior in replacing the kind of film withanother.

Additionally, the film fo used for packaging that has a greater widththan a tear tape can be cut with high accuracy according to thetoughness of the blade edge 23, and, when a scissors-like cuttingoperation is performed, the blade edge 23 can be allowed to exhibit itstoughness to such an extent as to compensate for errors in production,errors in installation, or errors in dimension, and the cuttingoperation can be prevented from being defectively performed because ofexcessive deviation of the blade edge 23.

Additionally, since a film-like air flow layer is formed by a leakagenegative pressure between the film fo moving along the inclined surface15 b of the fixed cutter 15 and the inclined surface 15 b, the film focan be smoothly carried to the blade edge 23 while weakening anadsorbing force.

Additionally, since the vibration preventing hook 44 is provided on theflank relief 15 b of the fixed cutter 15, the blade edge 23 pushed bythe blade edge 37 can be controlled not to deviate because of toughnesswhen a scissors-like cutting operation is performed with the rotarycutter 16, and, even when the film fo having a great width of 780 mm iscut with the fixed cutter 15 shaped like a thin planar band, the film focan be cut with excellent sharpness and with high accuracy over theentire width thereof without causing a cutting bend or jamming.

Additionally, the film fo can be reliably cut regardless of the kind ofmaterial of film fo. Moreover, since the film fo is carried and cutwhile being stably adsorbed, the film fo can be cut not only in a stateof being placed horizontally but also in a state of being placedobliquely or being turned upside down. Therefore, a high degree offreedom can be obtained when the device is mounted into the machine.

Next, another embodiment of the present invention will be described. Inthis embodiment, the same reference characters as in the film cuttingdevice 5 according to the aforementioned embodiment are given to thesame or similar constituent parts or components, and description thereofis omitted.

FIG. 8 is a longitudinal section of a main part of a cutter unit of afilm cutting device 45 according to a second embodiment of the presentinvention.

As shown in FIG. 8, in a cutter unit 50, a rotary cutter 46 is fixedwith a fixing bolt 48 to an inner wall directed in a rotationaldirection in a substantially V-shaped concave part 47 formed in an outerperipheral surface 33 a of a cylindrical cutter holder 33. A rotarycutter 46 that is substantially perpendicular to a rotational shaft 34shown in FIG. 8 is fixed substantially in the radial direction whenviewed sectionally, and a blade edge 37 juts out from the outerperipheral surface 33 a of the cutter holder 33 and is held at thejutting out position.

The blade edge 37 of the rotary cutter 46 is disposed at an offsetposition deviated by a distance D behind in the rotational directionwith respect to a virtual reference line L passing through therotational shaft 34. The blade edge 37 of the rotary cutter 46 is heldin a state of being slightly inclined with respect to a direction inwhich the blade edge 23 of the fixed cutter 15 extends, and the bladeedge 37 performs a scissors-like cutting operation while being in pointcontact with the blade edge 23 of the fixed cutter 15 in accordance withthe rotation of the rotary cutter 46.

It is permissible to install a guide member 49 that presses the film fo,which has been cut along the outer peripheral surface 33 a before andbehind the rotary cutter 46, against the top surface 8 a of the belt 8.In this case, two opposite surfaces of the cylindrical cutter holder 33may be excised, and both ends of the guide member 49 may be fixed withbolts 52 and 52, respectively.

A scissors-like cutting operation can be performed in relation to thefixed cutter 15 even when the rotary cutter 46 is disposed substantiallyin the radial direction as described above.

Additionally, the cutter unit 50 may be disposed in the vicinity of thedriving roller 9 b on the forward side in the conveying direction of theadsorption type carrying belt 8 as shown in FIG. 8. If so, anaccumulation unit B of boxes b can be subjected to body folding and bepackaged while being moved upward in the vicinity of the film f cut bythe cutter unit 50, i.e., in the vicinity of the driving roller 9 b onthe forward side in the conveying direction of the adsorption typecarrying belt 8. A more compact accumulating and packaging machine canbe produced by employing this structure.

Next, a modification of the film cutting device 5 according to theaforementioned embodiments of the present invention will be describedwith reference to FIG. 9.

The adsorption type carrying belt 8 on which the cutter units 13 and 50are disposed is not necessarily required to be planar or linear. Forexample, even when the top surface 52 of the adsorption type carryingbelt 8 is formed to be circularly arcuately curved as shown in FIG. 9,the cutter units 13 and 50 can be disposed on the top surface 52 of thebelt 8. As shown in FIG. 9, the top surface 52 of the adsorption typecarrying belt 8 is formed to be circularly arcuately curved when viewedfrom the side. The fixed cutter 15 is disposed at an appropriateposition on the top surface 52 of the adsorption type carrying belt 8substantially along a tangential direction, and the rotary cutter 16 isdisposed close to and substantially obliquely in front of the fixedcutter 15. The rotary cutter 16 is disposed along the outer peripheralsurface 33 a of the nearly cylindrical guide holder 33 in the same wayas in, for example, the first embodiment. The blade edge 37 of therotary cutter 16 performs a scissors-like cutting operation in relationto the blade edge 23 of the fixed cutter 15.

In this case, the fixed cutter 15, which has a substantially triangularsection when viewed longitudinally, may be disposed at the position ofthe flank relief 15 b on the forward side in the tangential directionwith respect to the top surface 52 formed to be circularly arcuatelycurved. Alternatively, the fixed cutter 15 may be disposed at a positionon the upstream side at which the inclined surface 15 a starts beingseparated from the top surface 52 of the adsorption type carrying belt 8in the tangential direction with respect to the top surface 52 of theadsorption type carrying belt 8. In any case, since the fixed cutter 15is formed to have a maximum height of about 3 to 5 mm, the film fo canbe smoothly guided to the blade edge 23 along the inclined surface 15 a.

According to this modification, the adsorption type carrying belt 8 isgreat in design freedom.

In the film cutting device 45 according to the second embodiment, thefilm fo is cut, and an accumulation unit B is then moved up in thevicinity thereof while subjecting a film f to body folding, and ispackaged with the film f. Instead, the following steps may be employed.In detail, an accumulation unit B is moved up before the film fo is cutby the cutter units, 13 and 50, and a film f that has been pushed outfrom the top surface 8 a of the belt 8 is subjected to body folding.Thereafter, the fixed cutter 15 and the rotary cutters 16 and 46 cut thefilm fo, and the accumulation unit B is packaged with a film f.

In the embodiment described above, the vibration preventing hook 44 ispressed against the flank relief 15 b of the fixed cutter 15. Instead ofthis structure, or in addition to this structure, the vibrationpreventing hook 44 may be disposed on a flank relief directed to theforward side in the rotational direction of the rotary cutters 16 and46. In this case, elastically deformable toughness is provided also tothe blade edge 37, as a matter of course.

Additionally, the flank relief 15 b and the like have a runaway groovehaving, for example, a substantially V-shaped cross section or a concavecross section when viewed longitudinally. However, if the wedge angle ofthe blade edges 23 and 37 is acute, the flank relief may have a planarshape without being limited to such a V-shaped cross section or aconcave cross section. In this case, it is recommended that the elasticdeformation of the blade edges 23 and 37 be restricted by pressing thevibration preventing hook 44 against the flank relief.

The rotary cutters 16 and 46 are not necessarily required to be disposedat an offset position. If a tangential line of the cutter holder 33 thatis drawn from the intersection of the blade edges 23 and 37 is directedto intersect with the top surface 8 a of the belt 8 when a film is cut,a load F of the blade edge 37 will be given in a direction being appliedto the fixed cutter 15.

The works accumulated and conveyed in the present invention are notlimited to tissue boxes b, and may be various articles of merchandise.

INDUSTRIAL APPLICABILITY

As described above, the film cutting device of the present inventionincludes a first cutter that has a blade edge at an end of a guidesurface inclined in a direction receding from a conveying means, and asecond cutter that cuts a film on the guide surface in cooperation withthe blade edge of the first cutter, and, in the film cutting device, thefirst cutter and the second cutter are relativity moved, and the bladeedge of the first cutter and a blade edge of the second cutter aregradually engaged with each other in an extending direction thereof,thus cutting the film. Therefore, the film can be cut in the widthdirection by separating the film from the conveying means by use of theguide surface and by engaging the first cutter and the second cutterwith each other.

Since the conveying means is an adsorption type carrying belt thatadsorbs the film, the film can be carried regardless of a difference inkind, such as rigidity or tension, of the film, and the film can be cutwhile being adsorbed regardless of the posture of the film in which thefilm is carried.

Additionally, since the blade edge of the first cutter is elasticallydeformable, and since the first cutter is provided with a displacementrestricting member that restricts an elastic deformation of the bladeedge when the film is cut, an error in dimension or in installation ofthe first and second cutters is absorbed, and the runaway of the bladeedge is restricted by the displacement restricting member even if thewidth of the blade edge is great. Therefore, the sharpness of the cuttercan be maintained, and the film can be cut with high accuracy.

Additionally, since the first cutter is shaped like a wide band, andsince the displacement restricting member is provided in a central areain an extending direction of the blade edge of the first cutter, theamount of deviation resulting from the toughness can be restrictedespecially in the central area where a great deformation is liable to becaused by the toughness.

Additionally, since the displacement restricting member is in contactwith the flank relief of the first cutter that is crossed with the guidesurface at the blade edge thereof, the toughness is secured, and adeviation caused by the toughness when the blade edges are pressed tocome into contact with each other can be restricted.

Additionally, since the second cutter is a rotary cutter rotatablearound a rotational shaft, and since the blade edge of the second cutteris installed so that a cutting force acts toward the first cutter when afilm is cut, it is possible to absorb minute pressure-contact chaoticmovement of the blade edge resulting from an error in dimension or ininstallation of the cutter.

Additionally, since the second cutter guides the following film in adirection of the conveying means by means of a backface of the secondcutter on a rear side in a moving direction subsequent to the blade edgethereof, a film part following the film that has been cut can be guidedonto the conveying means by pressing the film part down by means of thebackface of the second cutter.

Additionally, since the first and second cutters are held together as acutter unit and can be adjusted by being detached from the conveyingmeans, an engagement position of the first and second cutters can beindependently adjusted in a state in which the cutters are detached fromthe conveying means, and it is possible to perform excellent maintenanceof the positioning of the blade edges or the replacement of constituentelements.

Additionally, since the cutter unit is disposed so as to be adjustablypositioned in the direction in which the film is carried by theconveying means, the position at which the film is cut can be adjustedin forward and backward directions, and the overall device can be madecompact so as to be superior in size reduction and in economy, and acutting adjustment can be easily performed according to a difference inkind or usage of the film.

1. A film cutting device comprising: a conveyor for conveying a film; afirst cutter provided on the conveyor and having a blade edge at an endof a guide surface that is inclined in a direction of getting away fromthe conveyor; and a second cutter for cutting a film placed on the guidesurface in cooperation with the blade edge of the first cutter, whereinthrough a relative movement of the first cutter and the second cutter,and the blade edge of the first cutter and a blade edge of the secondcutter are gradually engaged with each other in an extending directionthereof in order to cut the film.
 2. The film cutting device accordingto claim 1, wherein the conveyor is an adsorption type carrying beltthat adsorbs the film.
 3. The film cutting device according to claim 1or 2, wherein the blade edge of the first cutter is elasticallydeformable, and the first cutter is provided with a displacementrestricting member that restricts an elastic deformation of the bladeedge when the film is cut.
 4. The film cutting device according to claim3, wherein the first cutter is shaped like a wide band, and thedisplacement restricting member is provided in a central area in anextending direction of the blade edge of the first cutter.
 5. The filmcutting device according to claim 1, wherein the displacementrestricting member is in contact with a flank relief of the first cuttercrossed with the guide surface at the blade edge thereof.
 6. The filmcutting device according to claim 1, wherein the second cutter is arotary cutter rotatable around a rotational shaft, and the blade edge ofthe second cutter is installed so that a load acts toward the firstcutter when a film is cut.
 7. The film cutting device according to claim1, wherein the second cutter guides a following film in a direction ofthe conveyor on a rear side in a moving direction subsequent to theblade edge thereof.
 8. The film cutting device according to claim 1,wherein the first cutter and the second cutter are held integrated as acutter unit, and can be removably adjusted with respect to the conveyor.9. The film cutting device according to claim 1, wherein the firstcutter and the second cutter are held integrated as a cutter unit, andthe cutter unit is disposed so as to be adjustably positioned in adirection in which the film is carried by the conveyor.